Which of the following modes is the most economical method of transmitting electrical power over long distances?
A. alternating current at low voltage and high current B. alternating current at high voltage and high current C. alternating current at high voltage and low current D. direct current at low voltage and high current Correct Answer: Option C C. alternating current at...
The core of a transformer is usually laminated in order to?
A. reduce magnetic leakage B. reduce eddy current C. prevent vibration of the transformer D. make magnetic reversal in the core much easier Correct Answer: Option B B. reduce eddy current
The magnetic relay is a device used for?
A. timing in sports B. storing magnetic field C. read the magnitude of magnetic flux D. controlling another circuit carrying larger current Correct Answer: Option D D. controlling another circuit carrying larger current
A 120Ω resistor dissipates 8 kJ of heat in 20s. Calculate the current through the resistor.
A. 5.8A B. 6.9A C. 30.0A D. 33.3A Correct Answer: Option A A. 5.8A
Two similar cells are used to light two similar lamps as illustrated in the diagrams above. In which of the circuit diagrams are the lamps brightest?
A. P B. Q C. R D. S Correct Answer: Option A A. P
Six dry cells each of e.m.f. 2.0 and internal resistance of 1.0Ω are connected in parallel across a load of 3.0Ω. Calculate the effective current in the circuit
A. 0.63A B. 0.50A C. 0.31A D. .22A Correct Answer: Option A A. 0.63A
The sound heard by a person after the reflection of the sound generated by him is called?
A. reverberation B. resonance C. echo D. audibility Correct Answer: Option C C. echo
Which of the following properties is an advantage of lead-acid accumulator over an alkaline accumulator?
A. possesses low internal resistance B. can be recharges C. has a shorter life span D. possesses high e.m.f Correct Answer: Option D D. possesses high e.m.f
When two like charges are brought together, the potential energy of the system formed will?
A. increase because work is done against the field B. increase because work is done by the field C. decrease because work is done by the field D. decrease because work is done against the field Correct Answer: Option D D. decrease because work is done against the...